1. Field of the Invention
The present invention relates to an ink and relates to an ink cartridge and an image-recording method using the ink.
2. Description of the Related Art
In image-recording methods, inks containing self-dispersible pigments as coloring materials have been used for improving the optical densities of images. Inks containing self-dispersible pigments can form images having relatively high optical densities, but have a problem of low scratch resistance of the images. Accordingly, it has been investigated to improve the scratch resistance of images by further adding a polyurethane polymer particle to an ink containing a self-dispersible pigment (Japanese Patent Laid-Open No. 2009-019198). Japanese Patent Laid-Open No. 2009-019198 describes an ink containing a polyurethane polymer particle in addition to a self-dispersible pigment.